Stereophonic ribbon cartridge



De- 26, 1967 TAKEO sHlGA ETAL 3,360,516.

STEREOPHONIC RIBBON CARTRIDGE I Filed June 25, 196s 5 sheetsneet 1 v INVENTORS 7&1960 S/ya //r'oAC/an/ 40u/ra' ATTORNEY Dec. 26, 1967 TAKEO SHIGA 'ETAL STEREOPHONIC RIBBON CARTRIDGEl Filed June' 25, 1965 5 Sheets-Sheet 2 ATTORNEY De@ 26, 1967 i TAKEo sHxGA ETAL 3,360,616

STREOPHONIC RIBBON CARTRIDGE Filed June 25, 1963 3 Sheets-Sheet 5 3 c 12a L2 18 L/.IJ 12b v, Y L, 16 L 11 y,

` INVENTORS 75l/6o 570g a /V/'favfan Mmc( ra BYZ': v ATTORNEY United States Patent C 3,360,616 STEREOPHONIC RIBBON CARTRIDGE Takeo Shiga and Hirokuni Kimura, Kawasaki, Japan, as-

signors to Nippon Columbia Kabushikikaisha (Nippon Columbia Co., Ltd.), Kawasaki, Japan, a corporation of Japan Filed June 25, 1963, Ser. No. 290,488 Claims priority, application Japan, Aug. 2, 1962, 37/33,178; May 1, 1963 (utility model), 38/ 32,360 3 Claims. (Cl. 179-100.41)

ABSTRACT OF THE DISCLOSURE A stereophonic ribbon cartridge having a pair of conductors for the right and left channels stretched to vibrate in a magnetic field and a stylus arm connecting a stylus tip to the vibrating conductors whereby the total voltage induced in one of the conductors relates substantially to one stereophonic channel -only and the total voltage induced in the other conductor relates substantially to the other stereophonic channel.

This invention relates to a cartridge for sterephonic use and more particularly to a novel ribbon type cartridge.

One object of this invention is to provide a ribbon type cartridge, the frequency response -characteristic of which is wide and excellent on the basis of a novel concept.

Another object of this invention is to provide a ribbon type cartridge in which the mass, inertia and the pressure of a stylus are small.

A yet another object of this invention is to provide a ribbon cartridge for stereophonic use, having short conductor vibrations to improve transient responsive characteristics.

Other objects, features and advantages of this invention will become apparent from the following description taken in conjunction with the accompanying drawings, in which,

FIGURE l is a schematic bottom plan view illustrating an example of a ribbon cartridge for stereophonic use according to this invention;

FIGURE 2 is its front view;

FIGURE 3-A, B and C are schematic diagrams of va-rious operating conditions, for explaining this invention;

FIGURE 4 is a bottom plan view of another example of the ribbon cartridge for stereophonic use according to this invention;

FIGURE 5 is front view of FIGURE 4;

FIGURE 6 is a side view showing a permanent magnet and a yoke;

FIGURE 7 is a cross-sectional view along -the line A-A in FIGURE 4;

FIGURE 8 is a cross-sectional view of the main portion of the cartridge in FIGURE 7 further enlarged; and

FIGURE 9 is an enlarged cross-sectional view along the line B-B in FIGURE 4.

In FIGURES l and 2, 1 is a permanent magnet composed of a magnet and a yoke, and a center piece 2 made of permeable magnetic material is disposed between magnetic poles 1a and 1b of the magnet 1, forming air-gaps g1 and g2 respectively between the magnetic pole 1a and the center piece 2 and between the magnetic pole 1b and the center piece 2. In these `air-gaps, there are established substantially homogeneous magnetic fields. For this purpose the end faces of the magnetic poles 1a and 1b and those of the `center piece 2 may form substantially parallel planes.

In such air-gaps, metallic Wires or metallic ribbons R1 and R2 are -respectively disposed along the length of the air-gaps, namely the metallic Wires or ribbons R1 and R2 are placed in parallel to each other in the air-gaps g1 and g2. The ends of the two metallic Wires or ribbons R1 and R2 are secured respectively to stationary parts S1, S1' and S2, S2', to which are connected output terminals t1, t1 and t2, t2. A stylus 3 is mounted substantially at the center positions of the two metallic wires or ribbons R1 and R2. This stylus may preferably be connected to the metallic wires or ribbons rigidly. In the drawings the stylus 3 is integrally composed of a pair of stylus arms 3a and 3b and a stylus tip 3c, and these stylus arms are coupled directly with the metallic wires or ribbons.

The cartridge of this invention may be applied to 45-45 lstereophonic records now in use. The sound groove of this type of stereophonic record has the right and left walls inclined 45 degrees with respect to the vertical and horizontal planes, and the walls are cut respectively according to the right channel signal and left channel signal after modulation. Therefore, its composite vector may be decomposed into the vertical component and horizontal component.

In FIGURE 3-A the stylus tip 3c is at a standstill in the center of the sound groove 4. In this case the horizontal line H H connecting the two metallic wires or ribbons R1 and R2 and the vertical line V-V passing through the center of the stylus 3 cross at a right angle to each other. C is its intersecting point. When the stylus is at Ia standstill like this no output voltage is obtained at the terminals t1, t1 and t2, t2.

FIGURE 3-B illustrates an example in which the stylus vibrates in the horizontal direction only. In this case the metallic wires or ribbons R1 and R2 vibrate in the opposite directions to each other with the intersecting point C as the fulcrum, accordingly the lines H-H and V-V intersect the horizontal and vertical lines obliquely. It will easily be understood that the metallic wires or ribbons R1 and R2 may vibrate with the intersecting point C as the fulcrum because they are fixed at their both ends. When the stylus vibrates in the horizontal direction only, currents which are antiphase to each other ow in the metallic wires or ribbons R1 and R2.

In FIGURE 3-C the stylus 3 vibrates in the perpendicular direction only, at this time the metallic wires or ribbons R1 and R2 do not vibrate with the intersecting point C as the center and the line connecting the metallic wires or ribbons R1 and R2 vibrates vertically, intersecting the line V-V at a right angle. Therefore the intersecting point C vibrates vertically. When the stylus thus vibrates in the perpendicular direction, currents which are in-phase to each other ow in the metallic wires or ribbons R1 and R2.

As is apparent from the foregoing, antiphase currents are produced in the metallic wires or ribbons R1 and R2 upon vibration in the horizontal direction, so that if, for example the terminal t1 of the metallic wire or ribbon R; is grounded and the terminal t1 is made to be the hot side, the terminal t2' of the metallic wire or ribbon R2 is made to be hot and the terminal t2 is grounded. In this case, the structure of the stylus and its -coupling means to the metallic wires or ribbons R1 and R2, namely the position of the intersecting point C must be considered in order that the vertical component of the speed due to the rotation of the metallic wires or ribbons R1 and R2 owing to the vibration in the horizontal direction of the stylus and the speed due to the vertical vibration may become equal with respect to the recorded sound equivalent in the horizontal and vertical directions (with respect to the 45`45 sound grooves).

If the stylus 3c follows a groove 4 having right and left channel signals cut in the walls R and L, respectively, in-phase voltages, for example e, will be induced in conductors R1 and R2, due to the vertical component of the signal, in phase with the said right channel signal, will,

since the vertical component of motion has an opposite phase to that of the corresponding right channel signal, be

where v is the magnitude of the induced voltages corresponding to the horizontal and vertical components of the left channel lrecorded signal.

The total voltages, E1 and E2, induced in conductors R1 and R2, respecively, due to both right and left channel recorded signals, will be Thus, conductor R1 has a resultant induced voltage corresponding to the right channel recorded signal and conduc-tor R2 and a resultant induced voltage coresponding to the left channel recorded signal. The pick-up cartridge of this invention thus separates the recorded signals of the two stereophonic channels, converting them into electric signals at the same time.

In the foregoing, -the air-gaps g1 and g2 are formed by arranging the center piece 2 between the magnetic poles 1a and 1b, an-d the metallic wires or ribbons are disposed in the air-gaps, by which the stereophonic signals are obtained, but the same effect may be obtained without using the center piece. As the coupling means of the metallic wires or ribbons and the stylus tip, although the stylus itself having the stylus tip is used in the drawing, a suitable vibration transmitter can be interposed be-tween the stylus and the metallic wires or ribbons.

FIGURES 4 through 9 illustrate another example of this invention, in which a conductive loop wound in a plurality of turns is used in place of a strip of ribbonshaped metal to enhance its efficiency.

1 is a permanent magnet and 2 is a yoke coupled therewith, forming an air-gap g between their confronting free ends. In the air-gap g, there are disposed in parallel a conductor L for the right channel use and another conductor L20 for the left channel use respectively wound in a plurality of turns in a taut condition. Accordingly one magnet is used in this embodiment.

Referring now to FIGURES 8 and 9, its structure will hereinafter -be explained. That is, a loop L1 wound in a desired number of turns, for example ten turns is wound on a bobbin 11 to form a conductor for the left channel use and in parallel thereto another loop L2 wound in the same number of turns is formed for the right channel use. These loops are contained .in a holder 12 of non-magnetic material as shown in FIGURES 8 and 9. In this case, as shown in AFIGURE 9 the bobbin 11 is provided with a concave groove 13 at its upper portion and some portions of the loops are stretched over the concave groove, so

that only the portions L10 and L20 across the groove 13 are permitted to vibrate in the air-gap g. The other portions of the loops L1 and L2 are made not to vibrate by being held by the margin 11a and 11b of the bobbin 11.

That is, the loops are supported in a manner so that oneportions thereof may vibrate in a magnetic field, and these vibrating portions are connected by a stylus arm 3. The stylus arm is to connect the loop portions over the concave groove and capable of vibrating, which arm is supported by a supporting line 14 and a stylus ltip 3C is mounted on the outside thereof.

The aforementioned parts are enclosed in the holder 12 of non-magnetic material and it is so constructed that the stylus tip 3C projects out from the opening 15 of the holder. In order to attach the holder 12 detachably. in the air-gap previously described, the marginal edges 12a and 12b of the holder are folded outwards and set in the margin of the yoke 2, thus the holder fits on the yoke 2 resiliently. Terminals t1, t2 and t1 and z2 ofthe respective loops are led out by a suitable means. In this example terminal plates 16 and 17 are provided on the side portions ofthe yoke 2, through which the yoke is connected to the input side of an outside amplifier not shown. As is apparent from FIGURE 9, a supporting line 14 is stretc-hed between bobbin Stoppers 18 and 18 disposed on the outside of the bobbin 11 and the loops L1 and L2 Wound thereon.

When effecting the stereophonic playback by contacting the stylus tip with the sound groove of a disc by the use of the cartridge of this example constructed as described above, signals of the left channel are taken out from, for example one loop L1 and those of the right channel are produced from the other loop L2. Thus the stereophonic playback may be carried out.

In the cartridge of this example the conductor stretched in the air-gap is wound in several or some dozen turns, so that the current due to induction is larger than that of a single metallic ribbon and its impedance becomes higher and accordingly the matching to the input side of the amplifier is favorable to obtain a larger signal current as a whole.

As shown in FIGURE 9, one portion of the loops Wound in suitable turns, namely the portions L10 and L20 across the concave groove 13- are vibrated in the magnetic field in the air-gap in response to the vibration of the stylus tip, as a result of this, induced currents are produced in these loops L1 and L2 to obtain currents for signals of the right and left channels, and these currents are applied to their speakers through the amplifier. In this case it must be noted that the loops except the portions L10 and L20 across the concave groove are secured onto the bobbin 11 through the use of, for example a suitable adhesive and hence they do not vibrate in the magnetic field in response to the vibration of the stylus tip. If these portions vibrate, the induced currents produced in the whole loops cancel each other and as a result no output is produced.

According to this invention as described above, currents for the right and left signals may be made to be relatively large and further a ribbon conductor to lead out these currents is contained in a holder of non-magnetic material, which holder is mounted on a yoke detachably with respect to a magnetic field air-gap formed on the end portion of the yoke. Therefore, when the stylus tip has been worn or broken, its check and repair or replacement may easily be effected by removing the stylus holder from the yoke.

It will be apparent that many modifications and variations may be effected without departing from the scope of the novel concept of this invention.

What is claimed is:

1. In a stereophonic phonograph reproducer having a magnet system, a pair of conductors which are arranged to vibrate in the magnetic field established by said magnet system to produce signal currents for the right and left channels, a stylus arm attached to said pair of conductors, wherein the improvement comprises a stationary bobbin having a concave groove, said pair of conductors being mounted on said bobbin across said concave groove in a stretched condition in order to form a restricted vibrating portion responsive to vibrations of said stylus arm and a stylus tip in response to a groove of a stereo phonic record.

2. In a stereophonic phonograph reproducer having a magnet system, a pair of conductors which are arranged to vibrate in the magnetic eld estaablished by said magnet system to produce signal currents for the right and left channels, a stylus arm attached to said pair of conductors, wherein the improvement comprises: a stationary bobbin having a pair of supporting portions for said conductors, said pair of conductors being mounted on sai'l bobbin across, said pair of supporting portions in a stretched condition in order to form a restricted vi bratng portion responsive to vibrations of said stylus arrn and a stylus tip in response to a groove of a stereophonic record, said stationary bobbin being inserted into said magnetic eld.

3. A stereophonic phonograph reproducer as claimed in claim 2, wherein said pair of conductors are loops Wound with a plurality of turns.

References Cited UNITED STATES PATENTS FOREIGN PATENTS 5 1962 Germany. 8/ 1962 Germany. 5/ 1948 France.

15 BERNARD KONICK, Primary Examiner.

P. S'PERBER, Assistant Examiner. 

2. IN A STEREOPHONIC PHOTOGRAPHS REPRODUCER HAVING A MAGNET SYSTEM, A PAIR OF CONDUCTORS WHICH ARE ARRANGED TO VIBRATE IN THE MAGNETIC FIELD ESTABLISHED BY SAID MAGNET SYSTEM TO PRODUCE SIGNAL CURRENTS FOR THE RIGHT AND LEFT CHANNELS, A STYLUS ARM ATTACHED TO SAID PAIR OF CONDUCTORS, WHEREIN THE IMPROVEMENT COMPRISES: A STATIONARY BOBBIN HAVING A PAIR OF SUPPORTING PORTIONS FOR SAID CONDUCTORS, SAID PAIR OF CONDUCTORS BEING MOUNTED ON SAID BOBBIN ACROSS SAID PAIR OF SUPPORTING PORTIONS IN A STRETCHED CONDITION IN ORDER TO FORM A RESTRICTED VIBRATING PORTION RESPONSIVE TO VIBRATIONS OF SAID STYLUS ARM AND A STYLUS TIP IN RESPONSE TO A GROOVE OF A STEROPHONIC RECORD, SAID STATIONARY BOBBIN BEING INSERTED INTO SAID MAGNETIC FIELD. 